ITPG20130034A1 - LIGHT GUIDE FOR MIXED LIGHTING SYSTEMS. - Google Patents

Description

Description of the industrial invention from the title:

Light guide for mixed lighting systems

in the name of HEADWAY Srl, registered office in Via Bartocci 18, Terni.

5 Designated inventors: Ermanno Imbergamo, Luigi Vaccaro, Vincenzo Cascioli

Field of application of the invention

The present invention relates to a particular light guide for use in the lighting engineering field, as part of a lighting system.

State of the art

It is known that there are lighting systems in which the light produced by a luminous source placed in a certain point of the space is transported and used in another point. Usually this is done through light guides.

It is known that there are light guides, for example in the form of optical fiber or hollow tubes with reflective internal walls.

In both cases, a light entering the device can be led to the exit terminal.

In the case of optical fiber, there are also commercial variants, of the lateral emission optical fiber type, in which the incoming light is emitted / diffused in a non-directional manner uniformly along the entire length of the fiber.

Both types of light guide find application in the lighting engineering field, each with its own advantages and disadvantages. In particular, hollow tubes can carry sufficient light intensities for the functional lighting of work or household environments, but they are difficult to handle from a mechanical point of view as they are rigid and bulky. The optical fiber is flexible and easy to handle, but it cannot carry sufficient light intensities for the functional lighting of environments, unless using optical fiber cables with a section so large as to be mechanically almost rigid, as well as optically inefficient due to the interstices between one fiber and another.

Furthermore, both types of light guides are very disadvantageous both in commercial terms, due to their high cost, and in environmental impact due to the large amount of energy required in their production process.

A first purpose of the present invention is to provide a light guide, optically efficient, economical, of simple production, easy to install in lighting systems, for functional and / or decorative lighting of environments.

Furthermore, it is known that there are lighting systems of the sunlight type and of the electric lamp type that use the aforementioned light guides to transport the light from the point of entry into the guide to the emission terminal in the environment to be illuminated. In the case of solar lighting systems, in order to compensate for any lack of sunlight, an auxiliary artificial lamp is also used. For example, the Parans fìber optic SkyLight @ solar lighting system (currently the most widespread of its kind) involves the use of a hybrid chandelier in which the terminal of an optical fiber cable carrying sunlight and an artificial lamp that lights up when the intensity of sunlight is less than a preset value. This entails the disadvantageous need for the presence of an electrical system for artificial lighting present in the environment to be illuminated, in addition to the solar light system. at risk, in which the presence of electric current could cause fire or explosion (deposits of gas, fuel, weapons and ammunition, ...).

A second object of the present invention is to provide a light guide that can simultaneously receive light from several light sources, for example from an artificial lamp and the sun, and therefore be able to transport it and diffuse it in the rooms to be illuminated. .

Summary of the invention

These and other purposes are achieved in accordance with the present invention through the use of a light guide, capable of transporting the light injected into it by one or more light sources and diffusing it from some of its predetermined points with different techniques depending on the desired lighting effect. The light can be emitted in a directional way, like the light beam of a hole, or in a diffused way over the whole space, like a neon tube, or in other ways. This invention is suitable for lighting engineering purposes both because of the possibility of creating decorative effects and functional lighting.

The incoming lights can come from artificial lamps of various types, for example LED, halogen, metal vapor, or come from a solar light capture system.

The light guide performs the triple function of transporting, diffusing and mixing (and incoming lights.

The light guide is modular, i.e. several pieces can be connected one after the other up to the desired length.

The light guide can be fitted with flexible or rigid light guide couplings to facilitate coupling with the incoming lights. These clutches can be equipped with a light sensor for measuring the intensity of the light entering the guide. The signal generated by said sensors can be used for the control (on / off / dimming) of the light sources entering the guide.

15The light guide can possibly be covered by protective / insulating films with respect to the surrounding environment.

It is known that in lighting technology sometimes the mixing of lights of different colors, coming from as many light sources, is used to carry out chromatic effects of various types, or starting from a series of white light sources, as many colored lights are obtained by means of chromatic filters which are then projected in superimposition. A further advantageous aspect of the present invention is that such effects can be more easily achieved by having the light guide described herein available. In fact, said light guide can receive at its input the light coming from several artificial lamps, transport it and emit it in a controlled manner, for example 5directional to the modes of a core bit, at desired points of light emission. Furthermore, the light guide can be configured with incoming light of a given chromatic spectrum, from which different chromatic spectra can be obtained at the exit from the light guide by virtue of the application of photo-luminescent materials at the light exit windows.

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Description of the figures

FIG 1, shows the entrance end (la) of the light guide, with a flexible light guide (lb) and a rigid light guide (le), the latter equipped with a light sensor (ld) for measuring the intensity of incoming light

FIG 2, shows a detail of a central unit (2a) of the light guide, in which two incisions (2b) are made from which part of the light (2c) comes out and travels along (as a light guide

FIG 3, shows a detail of a central unit (3a) of the light guide, in which surface abrasions (3b) are made from which part of the light (3c) comes out and travels along the light guide.

FIG 4, shows the final end (4a) of the light guide, where the light travels and exits completely from the oblique cut (4b). It also shows the blending mode of the light inside the bar and the light ejection cone. 15

Detailed description of the invention

The light guide according to the present invention is composed of the union of different units (FIGI, FIG2 and / or FIG3, FIG4). The first of said units (FIGI) can have couplings for the entry of the lights to be transported / mixed / diffused. On the central units (FIG2, FIG3) it is possible to carry out workings aimed at the exit of the light according to the desired modalities. The last unit (FIG4) can have a reflecting or diffusing end.

In the preferred embodiment, said units are of transparent solid material, for example acrylic plastic, and have the shape of a bar with a rectangular section 5 and a smooth surface. In general, they can be of any other transparent material, for example glass, and in the shape of a bar with a circular, triangular cross section and the like, or in the shape of a flat plate.

The couplings can be glued in the first unit or simply positioned against the stop by means of mechanical fixing. Said couplings can be made of flexible optical fiber cable, full curved shaped plastic / transparent glass tube, or hollow tube with reflective internal walls, or the like. "core") liquid, so as not to have optical inefficiencies due to the filling factor of the fibers

solid flament optics. In the case of coupling with very intense light sources, the most advantageous material for the connection is glass, as it is resistant to high temperatures. The material of the fitting can also be chosen to act as an optical filter for the light entering the light guide, for example by absorbing the infrared or ultraviolet components.

The light rays coming from the incoming lamps, have total reflection on the walls of the transparent bar in the bar / air interface and are thus bound to travel along the light guide. These reflections also play the role of mixing the light rays, so that after a few reflections the light circulating in the guide is perfectly homogeneous.

The mixed light that travels along the guide can come out of special "luminous windows" made along the bars. The preferred methods of light escape are:

1. Deep incisions made on the sides of the bar. The light comes out at 15 of the engravings. Each incision causes the light to escape in the form of a luminous cone having a direction orthogonal to the axis of the bar, by virtue of the phenomenon of total reflection inside the material of the bar. The deeper the incisions, the more light comes out.

2. abrasions made on the surface of the bar. There is a Lambertian emission of 0light in correspondence with the abrasions. The amount of light emitted depends on the roughness of the abmtions. With the same light emitted into the bar, the greater the emission, the rougher the abrasion.

3. holes drilled on the bar. The light comes out at 360 degrees, orthogonally to the axis of the hole. The quantity of light that comes out is greater the greater is the 5diameter of the hole.

4. Semi-transparent adhesive tape on the sides of the bar. The delta light emission occurs in the same way as in the case with abrasions, but it is obviously a more practical / economical method to practice. The only precaution to take is to choose an adhesive with a refractive index no less than that of the bar material, so that total reflection does not occur at the bar / adhesive interface.

5. painting of the surface of the bar with fluorescent pigments. The light is emitted by the paint having fluorescent pigments with colors determined by the chromatic qualities of the pigment. The emission is isotropic over the whole space

6. engravings inside the bar made with three-dimensional laser engraving technique. The light impacts the incision made inside the bar and is diffused.

Various lighting effects can be achieved by composing the previous methods. In particular, (I) it is possible to avoid light emission in a section of the guide, by not operating any of the previous methods on this section, (2) it is possible to obtain uniform light emission along the guide by practicing increasingly thicker light exit windows or more and more relevant. For example, in the case of the deep incisions referred to in method 1, the light entering the guide comes out uniform when the incisions are made all identical but at a decreasing distance along the guide or made equidistant along the guide, but of increasing depth.

The connection points between one unit and the next can be used as windows for light remission when the two bars are simply placed "against each other". bar which causes an escape of about 10% of the light passing through the junction. Alternatively, this light leakage can be avoided, by using an adhesive or optical gel for the connection of the two bars, in order to remove the air between a bar and the next.

The residual light that reaches the bottom of the last unit can be made to escape, for example perpendicular to the axis of the bar by making a cut at 45 degrees (FIG4) or it can be reflected back by a reflective film placed at the end.

When this light guide is used in dusty / dirty environments or in contact with aggressive chemical substances, it can be covered with a 5fluorothermoplastic insulating film, for example FEP or THV from Dyneon, which is transparent to visible light, chemically and thermally resistant, of index much lower refraction than that of acrylic plastic and glass, so it does not affect the light guiding properties of the bars used.

0Example of use "hybrid lighting": suppose you want to illuminate an environment with natural / artificial hybrid light. The natural light is collected by a solar collector with fiber optic output and connected to the input of the light guide described above. The sensor of light present along the light guide graft provides a signal that

Al indicates how much natural light is entering the light guide. An LED lamp with a sun-like color temperature and high color rendering is connected to the other input socket. The light intensity emitted by the LED can be increased / decreased corresponding to decreases / increases in the intensity of the natural light (for example when a cloud passes) entering the light guide signaled by the light sensor. The end user will benefit from lighting of constant intensity and by virtue of the mixing of the two incoming lights, he will not perceive which of the two sources the light comes from nor in what proportions.

Example of use "RGB": suppose you want to illuminate an environment with adjustable chromaticity light. Instead of using many light points inside the room, you can use three colored LEDs, one red, one blue and one green. Through three grafts their light can be led into the light guide and guided where desired. The color of the light exiting the guide will depend on the intensities of each of the three color components and can be adjusted as desired.

IS Example of use "tanker hold": suppose you want to illuminate the interior of the hold of a ship that transports petrol / fuels. Here the use of electricity is dangerous due to possible fires / explosions, even when the hold is unloaded because of the always present flammable vapors. A light guide of the type described above, coated with FEP phleorothermoplastic can be used. The light entering the guide could be that of the sun during the day and that generated by an artificial lamp during the night. The sunlight is collected by a solar light sensor placed on the deck of the ship, and guided by optical fiber to the lower floor where it finds the connection to the light guide. The light of an artificial lamp is positioned in a convenient point in proximity of the hold to be illuminated.

5The hold can be illuminated for a length of 10-20 meters using PMMA acrylic plastic rods.

Claims (1)

CLAIMS 1. Modular light guide with units made of smooth bars of transparent material, comprising couplings for the entry of delta light and "windows" for controlled emission of light, characterized by the fact that: - it is modular as a union of different units of which the first of said units can have couplings for the entry of the lights to be transported / mixed / diffused, on the central units can be carried out processes aimed at the exit of the light, the last unit can have a reflective or diffusing end - said "windows" for the emission of light include incisions made equidistant along the guide, but of increasing depth 2. Light guide according to claim 1 wherein said couplings are made as flexible optical fiber cable, transparent solid tube, or hollow tube with reflective internal walls 3. A light guide according to claim 2, wherein a light sensor is positioned along said couplings which measures the intensity of the light which is engaged at the entrance to the light guide